Arc Curve Sliding Contact Line
Recommended by DARUI Electric
In the operation of overhead contact lines, in order to ensure that the contact wire does not break under a certain tension, it is required to conduct a contact wire wear measurement at least once a year. When the wear of the contact wire reaches a certain level, it should be reinforced or replaced. If the average wear of the contact wire in the entire anchor section exceeds 25% of the cross-sectional area of that type of contact wire, it should be completely replaced. If the average wear does not reach 25% but local wear exceeds 30%, local reinforcement can be carried out. When local wear reaches 40%, it should be replaced.
The focus of wear measurement should be on positioning points, electrical connections, wire joints, center anchorages, phase separations, and sectioning joints. Use a vernier caliper to measure the residual height of the contact wire, and then refer to the wear conversion table for that type of contact wire to determine the wear area (the cross-sectional area worn away) at that location.
Contact wire stagger and pull-off values
The positioning device fixes the contact wire in the correct position, which is called positioning. The point where the positioning device's clamp fixes the contact wire is called the positioning point. The horizontal distance from the positioning point to the centerline of the pantograph's running track is called the stagger value in straight sections and the pull-off value in curved sections. The purpose of the stagger and pull-off values is to ensure uniform wear of the pantograph slide, and to prevent pantograph detachment and damage accidents.
In straight sections, the center of the pantograph coincides with the centerline of the track, and the stagger value of the contact wire is arranged symmetrically about the track centerline, with a standard of ±300mm. After speed increase, it is between 200 and 250mm; the pull-off value is between 350 and 450mm.
In curved sections, the pull-off value is related to the radius of the curve.
Energy-Saving Sliding Contact Line
Insulators for Overhead Contact Lines
Insulators are used to suspend and provide electrical insulation from grounded parts.
The insulators used on overhead contact lines are generally porcelain, made by adding quartz and feldspar to clay and firing them, with a smooth glaze on the surface.
Energy-Saving Sliding Contact Line The insulators used on overhead contact lines are divided into suspension and post types by structure; and into ordinary and anti-fouling types by surface length (i.e., leakage distance). In recent years, toughened glass suspension insulators have been widely promoted. These insulators have high mechanical strength (2 to 3 times that of porcelain insulators), good electrical performance (average breakdown strength 3.5 times that of porcelain insulators under impulse waves), long service life, resistance to aging, easy maintenance, and good self-cleaning properties. Their characteristic is "zero-value self-breakage", meaning that when the insulator loses its insulating performance or is mechanically overloaded, the shed automatically cracks and falls off, making it easy to detect and replace in time. In recent years, China has developed and used e?1 type epoxy resin insulators, fluoroplastic and silicone rubber rod-post insulators, and semi-x?5 type and semi-tx-25 type semiconductor glaze insulators. Semiconductor glaze insulators greatly extend the cleaning cycle of insulators, improve the reliability of power supply, and have good trial results, but they have disadvantages such as larger leakage current. A more ideal new type of insulator is the composite polymer insulator. This insulator is made by combining two polymer materials: one material enhances mechanical strength, and the other enhances insulating performance, so that the composite polymer insulator can meet the requirements of high mechanical strength, good insulating performance, impact resistance, arc resistance, and light weight. This is also the future development direction of insulators.
Note: The above information and technical parameters are compiled and released by Yangzhou DARUI Electric Co., Ltd.
